Why my object change material when using node shading
Hope it'll help somebody out there, i already found the answer after messing around with it. So here what I found
Clicking on the material names in the node editor will also change the material of whatever is currently selected (or the group of vertices that have been assigned that material).
If you want to edit different materials in the node editor that are all part of the same object you can use the "Slot 1" and "Slot 2" options to the left of the material name.
TLDR; it changes if you select (material icon), it'll changed whatever the material. To change anything in node for material (in green box). It'll make the baked texture remain as intended.